Senior private equity advisers this week warned that the structure of Cinven's £552m (€802m) acquisition of Partnerships in Care, the UK's largest chain of mental health hospitals, has provided further evidence that UK buy-out market is overheating.

The deal is structured with debt equal to nine times earnings before interest, tax, depreciation and amortisation (ebitda) against a typical multiple of five, and the price tag is understood to value the hospital chain at 12.5 times last year's earnings against a typical multiple of 10.